A variety of implantable medical devices (IMDs) for delivering a therapy, monitoring a physiological condition of a patient or a combination thereof have been clinically implanted or proposed for clinical implantation in patients. Some IMDs may employ one or more elongated electrical leads carrying stimulation electrodes, sense electrodes, and/or other sensors. Additionally or alternatively, some IMDs may include electrodes or other sensors positioned along the housing of the IMD. IMDs may deliver therapy to or monitor conditions of a variety of organs, nerves, muscle or tissue, such as the heart, brain, stomach, spinal cord, pelvic floor, or the like. Electrodes or other sensors on the IMD housing or carried by a lead are positioned at desired locations for delivery of electrical stimulation or sensing of physiological conditions. For example, electrodes or sensors may be carried at a distal portion of a lead. A proximal portion of the lead may be coupled to an implantable medical device housing, which may contain circuitry such as signal generation circuitry and/or sensing circuitry.
Some IMDs, such as cardiac pacemakers or implantable cardioverter defibrillators (ICDs), monitor the heart of the patient via sensing electrodes and deliver cardiac electrical stimulation therapies via therapy delivery electrodes. The electrodes may be carried by one or more implantable leads. The leads may be transvenous, i.e., implanted in the heart or a blood vessel through one or more veins. Other leads may be non-transvenous leads implanted outside the heart. In other cases, electrodes may be carried by a housing of the IMD. In any of these cases, the electrodes are used to sense cardiac electrical signals for detecting cardiac conditions and/or for providing electrical stimulation such as pacing pulses, cardioversion shocks or defibrillation shocks to address abnormal cardiac rhythms (such as bradycardia, tachycardia or fibrillation), heart failure or other cardiac conditions.
The IMD senses signals representative of intrinsic depolarizations of the heart and analyzes the sensed signals to identify normal or abnormal rhythms. Upon detection of an abnormal rhythm, the device may deliver an appropriate electrical stimulation signal or signals to restore or maintain a more normal rhythm. For example, an IMD may deliver pacing pulses to the heart upon detecting tachycardia or bradycardia, and deliver cardioversion or defibrillation shocks to the heart upon detecting tachycardia or fibrillation.
In general, a clinician selects values for a number of programmable parameters that control the sensing functions of the IMD and the cardiac electrical stimulation therapy to be delivered by the IMD. Numerous programmable parameters may be available for controlling both the sensing and therapy delivery functions. The programmer may be used to interrogate the IMD to retrieve values of control parameters that have been programmed into the IMD. The programmable parameters may be accessed by the clinician or another user interacting with a programmer that wirelessly transmits programming data to the IMD. The clinician may select parameters to be programmed and select a setting or value of the programmable parameter using the programmer.